The present invention relates to an improved fairing for mounting atop the operator's cab of a vehicle, particularly a truck, for reducing air resistance to forward movement of such a vehicle.
The generally flat, vertical forward surface of a large truck's cargo box or trailer usually extends higher than the top of the cab of the truck or its tractor unit, generating enough turbulence as the vehicle is operated to significantly affect fuel consumption. Air deflectors and fairings for mounting on top of the cabs of trucks are well known, particularly those designed for mounting atop the cab of a tractor unit of a tractor-trailer truck. Such fairings are used to provide a smoother pattern of flow or air over the top of the cab and along the top and sides of the trailer of such a truck in order to achieve increased fuel economy.
For example, Saunders U.S. Pat. No. 3,241,876 discloses deflectors which extend upwardly at a rearwardly inclined slope to cause the flow of air to separate from the top of a truck cab and to create an eddy between the rear of the deflector and the front of a trailer unit or box of such a truck. Other previously known devices are similar to the shape of a "V" blade snow plow or comprise transversely oriented rearwardly sloping convexly curved plates to be mounted on top of a cab at an appropriate angle to improve air flow patterns.
While the above-described devices provide a decrease in air resistance to a truck as a whole, the devices themselves are subject to the force of eddying currents of air which develop behind and beneath such devices, tending to lift them from their mounting position, or causing the devices to vibrate and rattle annoyingly, and making leaks through the cab top likely.
These previously known devices often require relocation of clearance lights atop a truck cab, in order to retain visibility of such lights when the air deflector is mounted in the proper location for effectiveness.
In order to overcome the aforementioned shortcomings of previously known cab-mounted fairings, the present invention provides a cab-mounted fairing which provides improved patterns of air flow around a moving vehicle, yet is not susceptible to being lifted from a vehicle cab by self-created turbulence.
The preferred embodiment of the fairing of the present invention comprises two major parts which are securely fastened to one another: a front member having an appropriate aerodynamic shape, and a rear panel extending generally vertically within an open rear side of the front member, closing the rear side of the fairing as a whole, thus substantially preventing turbulent air flow from acting on most of the underside of the fairing.
The preferred fairing of the invention is mounted on top of a vehicle on feet which support the fairing a predetermined distance above the top of the truck cab, providing visibility of clearance lights, located on the cab top, without requiring these lights to be relocated when the fairing is installed. The feet also permit the fairing to be mounted on cabs of various dimensions and contours by adjusting the location of the feet or using different feet to fit different vehicles.
It is therefore a primary objective of the invention to provide an improved fairing for reducing the air resistance of a vehicle such as a truck.
It is another important objective of the present invention to provide a cab-mounted aerodynamic fairing which is not susceptible to being lifted from the top of a vehicle by air turbulence.
It is a further objective of the present invention to provide a fairing which may be mounted on cab tops of different lengths.
It is a primary feature of the present invention that it provides a cab-mounted fairing whose back side is closed to reduce the effects of wind turbulence which would otherwise tend to lift the fairing from the cab top.
It is another important feature of the present invention that it provides a cab-mounted fairing having a rigid yet light-weight construction incorporating a rear panel located supportingly within the front member to provide internal support for the aerodynamic shape of the front member.
It is another feature of the present invention that is provides a fairing having an aerodynamic shape which promotes smooth flow of air around both the cab and the cargo-carrying body of a truck while preserving visibility of clearance lights mounted atop the cab of the vehicle.
It is a primary advantage of the present invention that it provides a fairing which is less susceptible than previously known cab-mounted fairings to being lifted free from the top of the cab on which it is mounted.
It is another important advantage of the present invention that it provides a cab-mounted fairing having greater strength than previously known fairings.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.